Process for breaking petroleum emulsions



Patented F eb. 22, 1938 UNITED STATES PATENT OFFICE PROCESS FOR BREAKINGPETROIEUM EDIULSIONS Melvin De Groote, University City, Bernhard Keiser,Webster Groves, Leonard L. Faure, Kirkwood, and Arthur F. Wirtel,Webster Groves, Mm,- assignors to The Tret-O-Lite' Company, Webster v ofMissouri Groves, Mo., a corporation No Drawing. Original applicationMarch is,

1936, Serial No. 69,222. Divided and this application March 15, 1937,Serial No. 131,006

constitutes the continuous phase the emulsion.

They are obtained from producing wells and from the bottom of oilstorage tanks, and are commonly referred to as cut oil", "roily oil,emulsifled oil and bottom settlings.

The object of our invention is to provide a novel and inexpensiveprocess for separating emulsions of the character referred to intotheircomponent parts of oil and water or brine.

Briefly described, our process consists in subjecting a petroleumemulsionof the water-in-oil type to the action of a treating agent ordemulsii'ying agent of the kind hereinafter described, thereby causingthe emulsion to break down and separate'into its component parts of oiland water or brine, when the emulsion is permitted to remain in aquiescent state after treatment, or is subjected to other equivalentseparatory procedures.

The treating agent or demulsifying agent contemplated by our processconsists of or comprises an alkylated, naphthalene mono-sulfonic byintroducing one, two or more alkyl groups into a naphthalene residue andthen producing the sulfonic acid. Due -to the corrosiveness of thesulfonic acid, it is the usual practice to employ the reagent in theform of a salt, such as am- 'monium salt, potassium salt, sodium salt,etc.

We have discovered that if a suitablealkylated naphthalene mono-sulfonicacid is'neutralized with cyclohexylamine, one obtains a reagent ofunusual effectiveness. There does not appear to be any suitableexplanation of this unusual superiority, and similarly, there doesnotseern to be any basis by which one could anticipate or foresee thisunusual effectiveness. Apparently, this marked improvement is notdirectly related to oil or water solubility, insofar that similarneutralization with other amines may yield compounds which'have agreater solubility in oily materials or in water, and yet are not nearlyas suitable and not nearly as effective in theirv demulsifying action.

Apparently, there is some unlooked-for cooperation or chemical orphysical-chemical relationship between the cyclohexylamine residue andthe sulfo-aromatic residue. The neutralization of other conventionalacidic demulsifying reagents with cyclohexylamine does not seem to,produce any marked improvement over the corresponding sodium orammonium salts, and in many cases, yields an inferiorproduct, thusindicating that apparently the increased value does not reside in anadditive effect, due to the c!- clohexylamine residue. Furthermore, theeffectiveness of cyclohexylamine apparently is not enjoyed by variousother amines which bear some similarity to this material, such asaniline, to-' luidine, propylamine, diamylamine, etc. In other words, ifthe same allwlatednaphthalene monosulionic acids which are employed toproduce the treating agent or demulsifying agent used in our process areneutralized with many other apparently kindred amines, one does notobtain a reagent that even begins to approach the effectivene'ss oi thedemulsifying agent used in our process. Similarly, if one'neutralizesother sulfonic acids, which are knownto ,be effective demulslfyingagents, such as petroleum sulfonic acids of the mahogany acid type, withcyclohexylamine, one does not obtain a more eflective demulsifyingagent, and indeed, one is more likely'to obtain a demulsiiying agentwhich is less effective.

Based on the results of actual tests obtained in a variety of emulsifiedcrudes occurring in a number of the major oil fields of the UnitedStates, the conclusion one. must inevitably reach is, that the resultobtained by uniting the two residues, 1. e., the cyclohexylamine residueand the described sulfo-aromatic residuejin a silmle molecule, resultsin an unlooked-fonunique quality, which could not be foreseen by thepresent knowledge of the art, and which produces'a demulslfying agentthat is particularly effective for a large number of emulsified crudeoils.

Alkylated naphthalene mono-sulfonic acids are produced commercially, andthe salts are used for a variety of purposes. They are generallyproduced from naphthalene, because there does 66 not appear tote anyadvantage in the use 'of a naphthalene derivative, such aschlor-naphthalene, alpha and beta naphthol, etc. In other words, onecould introduce the sulfcnic acid residue and the alkyl residues into asubstituted naphthalene, such as chlor-naphthalene, etc., just asreadily perhaps as in the case of naphthalene. However, such derivativesare more expensive and no advantage is obtained. Such simplederivatives, of course, are the chemical equivalent of naphthalene inthe manufacture of such mono-sulfonic acids as are employed in themanufacture of the present reagent. It is understood that the wordnaphthalene is hereinafter employed to include these derivatives,although, as pointed out, there is no advantage in using them, and theexpense usually would be prohibitive.

The general process of manufacturing the demulsifying agent contemplatedby our process, consists in converting the naphthalene into either thealpha or beta naphthalene sulfonic acid.

The alcohol employed, such as propyl alcohol, butyl alcohol, amylalcohol, hexyl alcohol, decyl alcohol, etc., is converted into the acidsulfate, such as propyl hydrogen sulfate. The naphthalene mono-sulfonicacid and the alkyl hydrogen sulfate are combined in proportions so thatone, two, three or even four alkyl groups are introduced into thearomatic residue. This condensation reaction is generally carried out inthe presence of an excess of sulfuric acid. In some instances, thevarious reactions, such as sulfonation, sulfation, condensation, etc.,are carried out simultaneously. Generally speaking, the di-alkvlated andtri-alkylated material appear to yield the most desirable type ofreagent. The presence of some mono-alkylated material, or

some tetra-alkylated material is not objectionable, and may even bedesirable.

It is obvious, of course, that the alkylated groups introduced might bederived from oleflnes, such as butylene, propylene, amylene, etc.,insofar that such oleflnes react directly with sulfuric acid, to producethe alkyl hydrogen sulfates. Of course, in addition to introducing suchalkyl residues of the kind described into the aromatic nucleus, onecould also introduce an alkyl residue from some other alcohol, as, forexample, an alkylated group derived from ethyl or methyl alcohol, or onemight introduce a group derived from an aryl, aralkyl, or'cyclo-alcohol, but regardless of whether or not one introduces suchother residues, it is necessary that at least one alkyl residue of thekind described, 1. e., having at least three carbon atoms and not morethan ten carbon atoms, be introduced into the naphthalene ring. Suchcompounds having some other residue present, such as a methyl residue,might be considered as being derived from methyl naphthalene, instead ofnaphthalene, and thus, would'fall within the class of chemicalequivalents previously noted. It is immaterial as to the particularalcohol employed, or the particular isomeric form of the alcoholemployed, although generally speaking, it is most desirable to use theone lowest in cost. It is immaterial whether one uses normal propylalcohol or isopropyl alcohol. It is immaterial whether one uses a normalbutyl or isobutyl alcohol. alcohol be a primary alcohol, or a secondaryalcohol, or a tertiary alcohol, or the like.

It is obvious that a large number of isomers can be produced in. themanufacture of the reagent employed inthe present process. For instance,although the sulfonic group may be intro- It is immaterial whether theduced into either the alpha or beta position, it is manifest that thealkyl group or groups can be introduced into various positions in regardto the position of the sulfonic acid residue. Apparently, as far as weare aware, one isomeric form is as effective as the other. Reference tothe compounds is not intended to indicate any particular isomer, unlessthe text clearly indicates some specific position.

Insofar that the most readily available alcohols, from the standpoint ofcost, are isopropyl alcohol, normal butyl alcohol, isobutyl alcohol, andamyl alcohol, it is our preference to produce our reagents from thesealcohols, and in some instances, it is desirable to introduce difierentalkyl groups, such as a propyl group and butyl group into the samesulfa-naphthalene residue.

In the actual manufacture of alkylated naphthalene mono-sulfonic acids,the completion of the desired chemical reactions is followed .by awashing process which removes the excess of sulfuric acid or othersulfonation, sulfation, or

condensation reagent employed. The acidic mass thus obtained isneutralized with cyclohexylamine in the same manner that sodium orpotassium or ammonium hydroxides might usually be employed. The finalproduct, if it represents a pasty or semisolid or a solid mass, isrendered suitable for industrial use by the ,addition of a solvent, suchas water, an alcohol, a coal tar solvent, 2. petroleum hydrocarbonsolvent, or in any similar manner.

The demulsifylng agent that we prefer to use in practising our processis obtained by a reaction in which three moles of isopropyl alcohol areunited with one mole of naphthalene by the customary sulfation,sulfonation and condensation reactions. The resulting mixture consistslargely of di-propyl naphthalene mono-sulfonic acids and tri-propylnaphthalene mono-sulfonic acids, with possibly small amounts ofmono-propyl mono-sulfonic acids and tetra-propyl mono-sulfonic acidspresent. Generally speaking, it is easier to conduct the reaction sothat the bulk of the sulfonic acid represents the beta type, althoughthe alpha type may be produced, if desired. The neutralized product isdiluted with one or more solvents, so as to reduce its viscosity to thatof ordinary castor oil, or slightly greater. The solvents which wepreferably employ are a mixture of two or more of the following: Water,denatured alcohol, kerosene, or tar acid oil.

Among the reagents which are particularly eflective are thecyclohexylamine salts of the following alkylated naphthalenemono-sulfonic acids, 1. e., mono-isopropyl naphthalene monosulfonicacid, di-isopropyl naphthalene monosulfonic acid, tri-isopropylnaphthalene monosulfonic acid, mononormal butyl naphthalenemono-sulfonicacid, di-normal butyl naphthalene mono-sulfonic acid,mono-isobutyl naphthalene mono-sulfonic acid, di-isobutyl naphthalenemono-sulfonic acid, mono-amyl naphthalene mono sulfonic acid, di-amylnaphthalene monosulfonic acid, tri-amyl naphthalene mono-sulfonic acid,mono-hexyl naphthalene mono-sulfonic acid, di-hexyl naphthalenemono-sulfonic acid, tri-hexyl naphthalene mono-sulfonic acid,

mono-octyl naphthalene mono-sulfonic acid, dioctyl naphthalenemono-sulfonic acid, monodecyl naphthalene mono-sulfonic acid, di-decylnaphthalene 'mono-sulfonic acid, mono-isopropyl, di-normal butylnaphthalene mono-sulfonic acid, di-isopropyl, di-normal butylnaphthalene monosulfonic acid, (ii-isopropyl, mono-amyl naphthasometimessome variation in nomenclature in regard to the salts derived fromstrong acids and various amines. For instance, the combination ofaniline, and hydrochloric acid, is often referred to as anilinehydrochloride. When aniline hydrochloride is treated with caustic soda,aniline is regenerated and sodium chloride formed. For this reason, andperhaps for other reasons, structural conditions are best expressed byreferring to the compound as a hydrochloride, in order to indicate thatone does not obtain the chloride of a quaternary ammonium compound. 7

Similarly, the reaction of cyclohexylamine with a sulfonic acid may beconsidered asproducing the cyclohexylamine salt, although for reasonspointed out, such salt might be looked upon as a cyclohexylaminehydrogen sulfonate, as well as being considered as a cyclohexylaminesulfonate. Insofar that it is perfectly clear as to the chemicalcomposition of the compound, it is immaterial which nomenclature isemployed.

cyclohexylamine salts, such as the hydrochloride, may react by doubledecomposition with alkali salt sulfonates in a suitable'medium toproduce the cyclohexylamine sulfonate.

Conventional demulsifying agents employed in the treatment of oil fieldemulsions are used as such, or after dilution with any suitable solvent,such as water, petroleum hydrocarbons, such as gasoline, kerosene, stoveoil. a coal tar product, such as benzene, .toluene, xylene, tar acidoil, cresol, anthracene oil, etc. Alcohols, particularly aliphaticalcohols, such as methyl alcohol, ethyl alcohol, denatured alcohol,pi'opyl alcohol, butyl' alcohol, hexyl alcohol, octyl alcohol, etc., maybe employed as diluents. Miscellaneous solvents, such as pine oil,carbon tetrachloride, sulfur dioxide extract obtained in the refining ofpetroleum, etc., may be employed as diluents. Similar- .ly, the materialor materials employed as the de-,

mulsifying agent'of our process may be admixed with one or more of thesolvents customarily used in connection with conventional demulsifyingagents. Moreover, said material or materials,

agents, such as demulsifying agents of the modified fatty acid type, thepetroleum sulfonate type,

the alkylated sulfo-aromatic type, in which the sulfonic hydrogen isneutralized by the use of some base other than cyclohexylamine.

It is well known that conventional demulsifying agents may be used in awater-soluble form,

or in an oil-soluble form, or in 'a form exhibiting both 011 and watersolubility. Sometimes they may be used in a form which exhibitsrelatively limited water solubility and relatively limited oilsolubility. However,since suchreagentsaresometimes used in a ratio of 1to 10,000, or 1 to 20,000, or even 1 to 30,000, such an apparentinsolubility in oil and water is not significant, because said reagentsundoubtedly have solubility within the concentration employed. This samefact is true in regard to the material or materials employed as thedemulsifying agent of our process.

' Having thus described our invention, what we claim as new and desireto secure by-Letters Patent is: I

1. A process for breaking petroleum emulsions of the water-in-oil type,which consists .in suba butylated naphthalene mono-sulfonic acid.

3. A process for breaking petroleum emulsions of the water-in-oil type,which consists in subjecting the emulsion to the action of ademulsifying agent comprising a cyclohexylamine salt of an amylatednaphthalene mono-sulfonic acid;

4. A process for breaking petroleum emulsions of the water-in-oil type,which consists in subjecting the emulsion to the action of ademulsifying-agent comprising a cyclohexylamine salt of a propylatednaphthalene mono-sulfonic acid..

MELVIN DE GROOTE. BERNHARD KEISER. LEONARD L. FAURE. ARTHUR F. WIRTEL.

